1. Field of the Invention
The present invention relates to contacts for microelectronic components such as semiconductor chips and associated circuit panels, connectors, sockets and related devices. Specifically, the present invention is directed to the forming of a wear resistant edge on the contacts on microelectronic components.
2. Description of the Related Art
Contacts for microelectronic components are typically formed from copper or other relatively soft or easily deflectable materials. The contacts engage terminals (such as pins or solder balls) on adjacent microelectronic components forming electrical connections. To improve the electrical connection, the contacts may wipe or otherwise abrade the pads or solder bumps as those elements are engaged, breaking through any oxide layer in order to electrically connect with the clean, un-oxidized material below.
Commonly assigned U.S. Pat. No. 5,802,699, the disclosure of which is hereby incorporated by reference herein, discloses a connector for mounting a microelectronic element to a substrate. In one embodiment, the connector has a body having a plurality of holes disposed in an array corresponding to an array of bump leads on the microelectronic device to be mounted. The connector also has an array of resilient contacts secured to the body in registration with the holes. Each contact is adapted to resiliently engage a bump lead inserted into the associated hole. An array of terminals are electrically connected to the contacts such that a microelectronic component can be connected to a substrate by bonding the terminals to the substrate and superposing the microelectronic element on the body. The bump leads on the component protrude into the holes and are engaged by the resilient contacts.
Certain embodiments disclosed in commonly assigned U.S. Pat. No. 5,632,631, the disclosure of which is hereby incorporated by reference herein, disclose microelectronic contacts having asperities to scrape a contacting solder ball or pad in order to break through the oxide layer. Preferably, the asperities are formed from beryllium copper or another conducting substance.
In many applications, microelectronic contacts and sockets are reused by removing one microelectronic element and replacing it with a second microelectronic element. For example, an assembly may be tested before bonding the contacts on the substrate to terminals on the microelectronic element. If the microelectronic element fails, it may be replaced by another microelectronic element, which is bonded to the substrate after passing the test. In another example, a substrate having sockets may be used as a test fixture for testing numerous successive microelectronic elements. In both cases, the sockets or contacts must withstand multiple wiping contacts with solder balls or pads on the microelectronic element.
Although the foregoing commonly assigned patents offer significant advantages, still further improvements in contacts are desirable.